Purchasing Plex Pass grants you access to premium features, not the software itself.
I read this as if you expected development to stagnate (there has not been an update to PHT in 4 years 
) I am confused that you would be upset about continued development instead of paying for software that hasnāt received any updates for so long.
Client and server updates are STILL being developed and released regularly. How does this not fit in the realm of Lifetime? Plex still has software offerings that will work for you (seriously give PMP another try it has improved greatly IMO)
If you wanted PHT to still work, then you should not have been updating your Plex Server.
